import java.lang.invoke.MethodHandle;
import java.lang.invoke.MethodHandles;
import java.lang.invoke.MethodHandles.Lookup;
import java.lang.invoke.MethodType;
 
class Ideone {
	static class Base {
		Object f(Object x) {
			return Base.class.getSimpleName() + x.hashCode();
		}
	}
 
	static class Ext extends Base {
		Object f(String x) {
			return Ext.class.getSimpleName() + x.length();
		}
	}
 
	public static Object f(Base x, Object arg) throws Throwable {
		Lookup lookup = MethodHandles.lookup();
		MethodType mt = MethodType.methodType(Object.class, arg.getClass());
		MethodHandle mh = lookup.findVirtual(x.getClass(), "f", mt);
		return mh.invoke(x, arg);
	}
 
	public static void main(String[] args) throws Throwable {
		Base x = new Ext();
		System.out.println(x.f("1"));   // sucks
		System.out.println(f(x, "1"));  // sig-polymorphic behavior
	}
}
 

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